Bioassay‐guided fractionation of lemon balm (Melissa officinalis L.) using an in vitro measure of GABA transaminase activity

A novel pharmacological mechanism of action for the anxiolytic botanical Melissa officinalis L. (lemon balm) is reported. The methanol extract was identified as a potent in vitro inhibitor of rat brain GABA transaminase (GABA‐T), an enzyme target in the therapy of anxiety, epilepsy and related neurological disorders. Bioassay‐guided fractionation led to the identification and isolation of rosmarinic acid (RA) and the triterpenoids, ursolic acid (UA) and oleanolic acid (OA) as active principles. Phytochemical characterization of the crude extract determined RA as the major compound responsible for activity (40% inhibition at 100 µg/mL) since it represented approximately 1.5% of the dry mass of the leaves. Synergistic effects may also play a role. Copyright © 2009 John Wiley & Sons, Ltd.     

Bioassay‐guided separation of citreorosein and other oestrogenic compounds From Polygonum cuspidatum

Citreorosein was isolated from P. cuspidatum as a new oestrogenic compound, together with emodin and its glucoside, by silica gel column chromatography and preparative high‐performance liquid chromatography sequentially. Oestrogenic activity was determined by a recombinant yeast assay. Copyright © 2008 John Wiley & Sons, Ltd.     

GABA‐modulating phytomedicines for anxiety: A systematic review of preclinical and clinical evidence

Anxiety disorders are chronic and functionally disabling conditions with high psychological stress, characterised by cognitive symptoms of excessive worry and focus difficulties and physiological symptoms such as muscle tension and insomnia. Gamma‐aminobutyric acid (GABA) is an inhibitory neurotransmitter within the central nervous system and is a key target of pharmacotherapies in the treatment of anxiety. Although current pharmaceutical treatments are often efficacious, they may cause undesirable side effects including cognitive decrements and withdrawal symptoms. Plant‐based “phytomedicines” may provide novel treatment options, to act as an adjunctive or alternative to existing anxiolytic medications. As such, we conducted a systematic review to assess the current body of literature on anxiolytic phytomedicines and/or phytoconstituents. An open‐ended search to 5 July 2017 was conducted using MEDLINE (PubMed), Scopus, and Cochrane library online databases and performed in a stepped format from preclinical to clinical investigations. Eligible studies must have had (a) in vitro evidence of GABA‐modulating activity, (b) animal studies using anxiety models to test an anxiolytic effect, and (c) human clinical trials. Ten phytomedicines were identified as having preclinical investigations showing interaction with the GABA system, in addition to human clinical trials: kava, valerian, pennywort, hops, chamomile, Ginkgo biloba, passionflower, ashwagandha, skullcap, and lemon balm. Collectively, the literature reveals preclinical and clinical evidence for various phytomedicines modulating GABA‐pathways, with comparative anxiolytic effect to the current array of pharmaceuticals, along with good safety and tolerability profiles.     

Parthenolide Inhibits the LPS‐induced Secretion of IL‐6 and TNF‐α and NF‐κB Nuclear Translocation in BV‐2 Microglia

Feverfew (Tanacetum parthenium [L.] Sch. Bip. [Asteraceae]) is a popular herbal treatment used to prevent and treat headache and migraine. Parthenolide (PTN), the sesquiterpene lactonic derivative that is the plant's major component, might be one of the ingredients that act on mediators of inflammation. In the present study, in cultured lipopolysaccharide (LPS)‐stimulated BV‐2 microglia pretreatment with PTN caused a dose‐dependent reduction of interleukin‐6 (IL‐6) secretion (29% by 200 nm, p < 0.001; 45% by 1 µm, p < 0.001; 98% by 5 µm, p < 0.001); at 5 µm, the highest concentration tested, it also reduced the secretion of TNF‐α (54%, p < 0.001). Western blotting analysis on separate cytoplasmic and nuclear extracts showed that PTN strongly reduced the translocation of nuclear factor (NF)‐κB to the cell nucleus. The reduction of microglial activation by inhibition of proinflammatory agents may help attenuate the onset and intensity of acute migraine attacks. These in vitro results provide an additional explanation for the efficacy of orally administered T. parthenium as an antimigraine agent. Copyright © 2012 John Wiley & Sons, Ltd.     

The regulation of protein kinase casein kinase II by apigenin is involved in the inhibition of ultraviolet B‐induced macrophage migration inhibitory factor‐mediated hyperpigmentation

Ultraviolet (UV) radiation elicits melanogenesis and pigmentation in the skin. Apigenin (4′,5,7‐trihydroxyflavone [AGN]) is a plant flavone contained in various herbs, fruits, and vegetables. We herein investigated antimelanogenic properties of AGN and the molecular mechanisms of the action of AGN. In UVB‐treated mice, AGN inhibited cutaneous hyperpigmentation and macrophage migration inhibitory factor (MIF) expression as a melanogenesis‐related key factor. In mouse keratinocytes, AGN inhibited the expression of MIF and also the related factors (e.g., stem cell factor and proteinase‐activated receptor 2) induced by MIF. In addition to ellagic acid as a casein kinase II (CK2) inhibitor, AGN suppressed CK2 enzymatic activity and UVB‐induced CK2 expression and subsequent phosphorylation of IκB and MIF expression. These results suggest that AGN inhibits UVB‐induced hyperpigmentation through the regulation of CK2‐mediated MIF expression in keratinocytes.     

Carotenoids with anti‐Helicobacter pylori activity from Golden delicious apple

Previously it was reported that hypophasic carotenoids of Golden delicious apple peel showed potent anti‐H. pylori activity (MIC₅₀ = 36 µg/mL), comparable to metronidazole (MIC₅₀ = 45 µg/mL). To further investigate the involved active carotenoids of the apple peel extracts, seven carotenoids were isolated for the current study: (all‐E)‐luteoxanthin, (all‐E)‐neoxanthin, (9′Z)‐neoxanthin, (all‐E)‐antheraxanthin, (all‐E)‐violaxanthin, (9Z)‐violaxanthin and (all‐E)‐lutein. The MIC₅₀ values of (all‐E)‐luteoxanthin, (all‐E)‐neoxanthin and (9′Z)‐neoxanthin were 7.9, 11 and 27 µg/mL, respectively. Other carotenoids and β,β‐carotene did not exhibit potent anti‐H. pylori activity (MIC₅₀ > 100 µg/mL). An examination of structure and function suggested that active carotenoids contained a monofuranoid ring or an allenic bond in addition to an epoxy group and an additional two or three hydroxyl substituents on the side group. Copyright © 2009 John Wiley & Sons, Ltd.     

Antifatigue activity of phenylethanoid‐rich extract from Cistanche deserticola

A phenylethanoid‐rich extract (ECD) of Cistanche deserticola Y.C. Ma, a holoparasitic plant and a valuable traditional Chinese medicine, was evaluated for antifatigue activity in ICR mice. ECD (0.25, 0.50, 1.00 g/kg) was administered orally to mice for 3 weeks. The swimming time to exhaustion was longer in the treatment groups (0.50, 1.00 g/kg) than in the control group (p < 0.01). The serum creatine kinase, lactate dehydrogenase and lactic acid levels were decreased significantly in the treatment groups compared with the control group, while the contents of hemoglobin and glucose were increased significantly. In conclusion, ECD appeared to enhance the swimming capacity of mice by decreasing muscle damage, delaying the accumulation of lactic acid and by improving the energy storage. These results provide scientific evidence for the traditional Chinese medical practice of C. deserticola. Copyright © 2009 John Wiley & Sons, Ltd.     

Melanin‐concentrating hormone‐1 receptor binding activity of pheophorbides isolated from morus alba leaves

The time‐resolved fluorescence technique based on melanin‐concentrating hormone (MCH) receptor subtype‐1 (MCH‐1 receptor) binding assay was adopted to carry out a bioassay‐guided fractionation of the methanol extract of Morus alba leaves. This fractionation and purification led to the isolation of two compounds identified as pheophorbide a methyl ester and 13²(S)‐hydroxypheophorbide a methyl ester. These active pheophorbides exhibited potent inhibitory activity in binding of europium‐labeled MCH to the human recombinant MCH‐1 receptor (IC₅₀ value; 4.03 and 0.33 ?M, respectively). Besides binding activity, the pheophorbides inhibited MCH‐mediated extracellular signal‐regulated kinase (ERK) phosphorylation in Chinese hamster ovary cells expressing human MCH‐1 receptor. These results suggest that pheophorbide a methyl ester and 13²(S)‐hydroxypheophorbide a methyl ester act as modulators of MCH‐1 receptor and MCH‐mediated ERK signaling. Copyright © 2009 John Wiley & Sons, Ltd.     

Bioguided isolation of angiotensin‐converting enzyme inhibitors from the seeds of Plantago asiatica L.

Ethanolic extract of the seeds of Plantago asiatica L. showed significant inhibitory activity of angiotensin‐converting enzyme (ACE) determined by monitoring the transformation from a substrate hippuryl‐histidyl‐leucine (HHL) to the product hippuric acid (HA) in vitro using an UPLC‐MS method. The bioguided fractionation of the extract resulted in the isolation of four ACE inhibitory active phenylpropanoid glycosides acteoside, isoacteoside, plantainoside D, and plantamajoside with IC₅₀ values of 2.69 mM, 2.46 mM, 2.17 mM, and 2.47 mM, respectively. Their structures were elucidated through the analysis of NMR, UV, IR and MS data. Our study is the first demonstration that Plantago asiatica L. and its major constituents have ACE inhibitory activity in vitro. It is assumed that the identified compounds contribute to the angiotensin‐converting enzyme‐inhibitory activity of the extract. Copyright © 2009 John Wiley & Sons, Ltd.     

Anticholinesterase activity of 7‐methoxyflavones isolated from Kaempferia parviflora

The rhizome of Kaempferia parviflora or kra‐chai‐dum (in Thai) is used traditionally as a folk medicine. The preliminary cholinesterase inhibitory screening of this plant extract exhibited significant acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Thirteen known methoxyflavones (1–13) were isolated and their structures were completely elucidated based on NMR analysis and compared with literature reports. Minor compounds 12–13 were reported for the first time from this species. The cholinesterase inhibitory test results showed that the highest potential inhibitors toward AChE and BChE were 5,7,4′‐trimethoxyflavone (6) and 5,7‐dimethoxyflavone (7), respectively, with the percentage inhibitory activity varying over 43–85%. The structure‐activity relationship study led to the conclusion that compounds bearing 5,7‐dimethoxy groups and a free substituent at C‐3 had a significant inhibitory effect at a concentration of 0.1 mg/mL, but those bearing a 5‐hydroxyl group reduced the inhibitory potency. On the other hand, flavones bearing a 3′‐ or 5′‐methoxy group did not influence the inhibitory effect. Interestingly, 5,7‐dimethoxyflavone (7) exhibited strong selectivity for BChE over AChE which may be of great interest to modify as a treatment agent for Alzheimer's disease. Copyright © 2009 John Wiley & Sons, Ltd.     

Complement‐fixing activity of fulvic acid from Shilajit and other natural sources

Shilajit has been used traditionally in folk medicine for the treatment of a variety of disorders, including syndromes involving excessive complement activation. Extracts of Shilajit contain significant amounts of fulvic acid (FA), and it has been suggested that FA is responsible for many therapeutic properties of Shilajit. However, little is known regarding the physical and chemical properties of Shilajit extracts, and nothing is known about their effects on the complement system. To address this issue, extracts of commercial Shilajit were fractionated using anion exchange and size‐exclusion chromatography. One neutral (S‐I) and two acidic (S‐II and S‐III) fractions were isolated, characterized and compared with standardized FA samples. The most abundant fraction (S‐II) was further fractionated into three sub‐fractions (S‐II‐1 to S‐II‐3). The van Krevelen diagram showed that the Shilajit fractions are the products of polysaccharide degradation, and all fractions, except S‐II‐3, contained type II arabinogalactan. All Shilajit fractions exhibited dose‐dependent complement‐fixing activity in vitro with high potency. Furthermore, a strong correlation was found between the complement‐fixing activity and carboxylic group content in the Shilajit fractions and other FA sources. These data provide a molecular basis to explain at least part of the beneficial therapeutic properties of Shilajit and other humic extracts. Copyright © 2008 John Wiley & Sons, Ltd.     

Anti‐allergic activity of principles from the roots and heartwood of caesalpinia sappan on antigen‐induced β‐hexosaminidase release

The dichloromethane extract of the roots and heartwood of Caesalpinia sappan exhibited potent inhibitory activity against β‐hexosaminidase release as marker of degranulation in rat basophilic leukemic (RBL‐2H3) cells, with inhibition of 98.7% and 87.5% at concentration of 100 µg/ml, respectively. These extracts were further separated by chromatographic techniques to give two chalcones and seven homoisoflavones. Among the compounds tested, sappanchalcone (2) possessed the most potent effect against allergic reaction in RBL‐2H3 cells with an inhibitory concentration (IC₅₀) value of 7.6 µM, followed by 3‐deoxysappanchalcone (1, IC₅₀ = 15.3 µM), whereas other compounds showed moderate and mild effects. The results suggested the following structural requirements of chalcones (1 and 2) and homoisoflavones (3‐9) for anti‐allergic activity: (i) chalcone exhibited higher activity than homoisoflavone (ii) vicinal hydroxylation at B‐ring of chalcone conferred higher activity than one hydroxylation; and (iii) for homoisoflavone, the hydroxyl groups at C‐3 and C‐4 positions decreased the activity. This is the first report of C. sappan for anti‐allergic activity. Copyright © 2009 John Wiley & Sons, Ltd.     

Bioassay-guided isolation of kaempferol-3-O-beta-D-galactoside with anti-inflammatory and antinociceptive activity from the aerial part of Calluna vulgaris L

Calluna vulgaris L. (Ericaceae) is used for the treatment of various inflammatory ailments in traditional medicines. In order to evaluate this ethnobotanical information, its anti-inflammatory and antinociceptive activities were studied using in vivo experimental models in mice. The ethanolic extract of the plant was first fractionated into five extracts; namely, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and water fractions. Among them, the EtOAc Fr. was found to be the most effective and was further subjected to bioassay-guided fractionation and isolation procedures. After successive column chromatography applications, on Sephadex LH-20 and silica gel, a component, which is responsible for the above-mentioned activities of this species of Turkish origin, was isolated and its structure was elucidated as kaempferol-3-O-beta-D-galactoside, a common flavonol derivative by means of spectral techniques.     

Potent modulation of P‐glycoprotein activity by naturally occurring phenylbutenoids from Zingiber cassumunar

Five phenylbutenoid derivatives from the rhizomes of Zingiber cassumunar Roxb. (Zingiberaceae) were evaluated for their P‐glycoprotein (P‐gp) inhibitory effects in a P‐gp over‐expressing multidrug resistant (MDR) human breast cancer cell line, MCF‐7/ADR. As a result, a phenylbutenoid dimer, (±)‐trans‐3‐(3,4‐dimethoxyphenyl)‐4‐[(E)‐3,4‐dimethoxystyryl]cyclohex‐1‐ene (1), exhibited highly potent P‐gp inhibitory activity, decreasing the IC₅₀ value of daunomycin (DNM) to 4.31 ± 0.40 µm in the cells (DNM IC₅₀ = 37.1 ± 0.59 µm ). The positive control, verapamil decreased the IC₅₀ value of DNM to 6.94 ± 0.40 µm . Three phenylbutenoid monomers, 2–4 from this plant, also resulted in a significant decrease in the IC₅₀ values of DNM compared with the control. In particular, compound 1 markedly enhanced [³H]‐DNM accumulation and significantly reduced [³H]‐DNM efflux compared with the control, and this effect was more potent than that of verapamil, a well‐known P‐gp inhibitor. These results suggest that compound 1 of Z. cassumunar can be developed as a potent chemo‐sensitizing agent that reverses P‐gp‐mediated MDR in human cancer chemotherapy. Copyright © 2008 John Wiley & Sons, Ltd.     

Anti‐complement activity of isolated compounds from the roots of Clerodendrum bungei Steud.

To determine the anti‐complement activity of natural diterpenes, chromatographic separation of the acetone‐soluble fraction from the roots of Clerodendrum bungei (Verbenaceae) led to the isolation of five diterpenoids. An acetone‐soluble extract of the roots of C. bungei exhibited significant anti‐complement activity on the classical pathway complement system, which was expressed as total hemolytic activity. Five compounds isolated from the roots of C. bungei, namely 12‐O‐β‐d ‐glucopyranosyl‐3,11,16‐trihydroxyabieta‐8,11,13‐triene (1), 3,12‐O‐β‐d ‐diglucopyranosyl‐11,16‐dihydroxyabieta‐8,11,13‐triene (2), ajugaside A (3), uncinatone (4) and 19‐hydroxyteuvincenone F (5). Compounds 1, 2, 3, 4 and 5 showed inhibitory activity against complement system with 50% inhibitory concentrations (IC₅₀) values of 24 µm , 138 µm , 116 µm , 87 µm and 232 µm . Among the compounds tested, 1 showed the most potent anti‐complement activity (IC₅₀, 24 µm ). Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of Rubiadin isolated from Prismatomeris connata on anti‐hepatitis B virus activity in vitro

Prismatomeris connata was a kind of Rubiaceae plant for treatment of hepatitis, hepatic fibrosis and silicosis. Whereas, the effective components of Prismatomeris connata remains unexplored. The aim of this study was to investigate the inhibitory effects and mechanisms of Rubiadin isolated from Prismatomeris connata against HBV using HepG2.2.15 cells. The levels of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B core antigen (HBcAg) in the supernatants or cytoplasm were examined using by enzyme‐linked immunosorbent assay. HBV DNA was qualified q‐PCR. Rubiadin was isolated by silica gel column. The structure of the compound was elucidated by HPLC, FT‐IR, ¹H‐NMR, ¹³C‐NMR and identified as 1,3‐Dihydroxy‐2‐methyl‐9, 10‐anthraquinone. Rubiadin significantly decreased HBeAg,HBcAg secretion level and inhibit HBV DNA replication. Rubiadin inhibits the proliferation of the cells and HBx protein expression in a dose‐dependent manner. The intracellular calcium concentration was significantly reduced. These results demonstrated that Rubiadin could inhibit HepG2.2.15 cells proliferation, reduce the level of HBx expression, and intracellular free calcium, which might become a novel anti‐HBV drug candidate.     

Cytotoxic activity of Secondary Metabolites from Marine‐derived Fungus Neosartorya siamensis in Human Cancer Cells

Compounds isolated from the marine sea fan‐derived fungus Neosartorya siamensis (KUFA 0017), namely, 2,4‐dihydroxy‐3‐methylacetophenon (1), chevalone C (2), nortryptoquivaline (4), tryptoquivaline H (6), tryptoquivaline F (7), fiscalin A (8), epi‐fiscalin A (9), epi‐neofiscalin A (11) and epi‐fiscalin C (13) were tested for anti‐proliferative activity by MTT assay, DNA damage induction by comet assay, and induction of cell death by nuclear condensation assay on colon HCT116, liver HepG2 and melanoma A375 cancer cell lines. Compounds 2, 4, 8, 9, 11 and 13 presented IC₅₀ values ranging from 24 to 153 μM in the selected cell lines. Cell death was induced in HCT116 by compounds 2, 4 and 8. In HepG2, compounds 4, 8, 9 and 11 were able to induce significant cell death. This induction of cell death is possibly not related to genotoxicity because none of the compounds induced significant DNA damage. These results suggest that selected compounds present an interesting anti‐proliferative activity and cell death induction, consequently showing potential (specifically epi‐fiscalin C) as future leads for chemotherapeutic agents. Further studies on mechanisms of action should ensue. Copyright © 2016 John Wiley & Sons, Ltd.     

Wound healing and protease inhibition activity of Bacoside‐A,isolated from Bacopa monnieri wettest

Bacopa monnieri (L.) Wettest. (Scrophulariaceae) is a well‐known medicinal herb. In the Indian system of medicine it is known as Brahmi (Sanskrit) and Indian water hyssop. Methanolic extract of Bacopa monnieri and its isolated constituent Bacoside‐A were screened for wound healing activity. Bacoside‐A was screened for wound healing activity by excision, incision and dead space wound on Swiss albino rats. Significant wound healing activity was observed in both extract and the Bacoside‐A treated groups. The SDS‐PAGE caseinolytic zymogram analysis of inhibition of matrix metalloproteases (MMPs) enzyme from the excision wound by Bacoside‐A, an isolated constituent, was done with the concentrations 100 and 200 μmg/ml. In Bacoside‐A treated groups, epithelialization of the excision wound was faster with a high rate (18.30 ± 0.01 days) of wound contraction. The tensile strength of the incision wound was increased (538.47 ± 0.14 g) in the Bacoside‐A treated group. In the dead space wound model, the weight of the granuloma was also increased (89.15 ± 0.08 g). The histological examination of the granuloma tissue of the Bacoside‐A treated group showed increased cross‐linking of collagen fibers and absence of monocytes. The wound healing activity of Bacoside‐A was more effective in various wound models compared to the standard skin ointment Nitrofurazone. Copyright © 2010 John Wiley & Sons, Ltd.     

Bioactivity-guided isolation of polyacetylenes with inhibitory activity against NO production in LPS-activated RAW264.7 macrophages from the rhizomes of Atractylodes macrocephala

Ethnopharmacological relevance

The rhizome of Atractylodes macrocephala (Compositae) is one of the most well-known traditional Chinese medicine in China, Japan and Korea, which has a long history of use for the treatment of splenic asthenia, edema, anorexia, and excessive perspiration, etc. As active compounds of anti-inflammatory activity of this medicinal plant have not been fully elucidated, the aim of this study was to isolate and identify the active constituents inhibiting nitric oxide (NO) production from the rhizomes of A. macrocephala.

Materials and methods

Inhibitory activity against NO production in lipopolysaccharide-activated RAW264.7 macrophages was evaluated by Griess reaction. Fifteen polyacetylenes were isolated from the active ethyl acetate extract using activity-guided screening. The structures of all compounds were elucidated by spectroscopic methods and comparison with published data. The compounds were further tested for their inhibitory activity against NO production.

Results

Seven new polyacetylenes, named atractylodemaynes A–G (1–7), along with eight known ones (8–15) were isolated. Compound 14 was isolated for the first time from the rhizomes of A. macrocephala. The study showed that the tested compounds exhibited inhibitory activity against NO production in a dose-dependent manner. Among them, compounds 10, 11 and 12 had relatively stronger inhibitory effect with IC₅₀ values of 28, 23 and 19 μM, respectively.

Conclusion

The results demonstrated that the polyacetylenes might greatly contribute to the anti-inflammatory activity of the rhizomes of A. macrocephala.